ALEXANDRIA, Va., July 3 -- United States Patent no. 12,344,391, issued on July 1, was assigned to HITACHI LTD. (Tokyo).
"Electric propulsion device" was invented by Hironobu Yamakawa (Tokyo), Kisho Ashida (Tokyo) and Yuji Enomoto (Tokyo).
According to the abstract* released by the U.S. Patent & Trademark Office: "Provided is an electric propulsion device 106 including a propeller 131 and a motor 121 for rotating the propeller, wherein the propeller includes a rotary boss 132 secured to a rotating shaft 123 of the motor, and blades 133 protruding radially outward from the rotary boss. Further, the blades include a base end portion with an airfoil continuously changing such that a trailing edge comes to be in parallel to the rotating shaft ...